In an X-ray inspection, a detection unit with a detector is provided. The detection unit detects transmitted amounts of the X-rays generated by an X-ray generator and transmitted through the object in each of n-number X-ray energy bins (n is a positive integer of 2 or more) which are set in advance to the X-rays, and outputs detection signals corresponding to the transmitted amounts. An information acquisition unit acquires, based on the detection signal, information showing a thickness t of the object and an average linear attenuation coefficient μ in a transmission direction of fluxes of the X-rays, in each of the energy bins. A pixel data calculation unit calculates, based on the acquired information, pixel data composed of pixel values each obtained by multiplying addition information by the thickness t. Addition information is obtained by mutual addition of the average linear attenuation coefficients μ in the respective energy bins.
